Method and apparatus for conditioning metal bodies



,-;1 J. H. BUCKNAM ETAL 2,309,096

METH QD AND APPARATUS FOR CONDITIONING METAL BODIES Filed Jan. 27, 1940 2 Sheets-Sheet 1 iNVENTORS V 7 I00 5 v g JAMES H. BUCKNAM Y l l EDWARD MEINCKE Y W5 THEODORE W.ESELGROTH v ATTORNEY Jan. 2, 1943 J, H BUQKNAM ETAL, 2,39fi6 METHOD ANDAPPARATUS FOR CONDITIONING METAL BODIES 2 SheetsSheet 2 INVENTORS JAMESIH. BUCKNAM EDWARD MElNCKE THEODE w. ESELGROT'H TRNE Filed Jan. 27, 1940 METHOD AND The invention relates to metal conditioning and more particularly to animproved method and apparatus for thermochemically' conditioning surfaces of ferrous metal bodiea'such as slabs,

billets, blooms and the like.

In the artof desurfa'cing a ferrous metal body,

such as a steel billet,a heating flame is first di- ARATUS FUR COI- TIONINQ METAL BODES James H. Bucknam;v Crawford, and Edward l\Ieincke,Roselle Park, N. J., Theodore W. Eselgroth, Gary, Ind., assignors to The Linda Air Products Company, a corporation of Ohio Application January 27,1940, Serial No. 315,896

24 c. (or. res- 9) rected against a portion of a surface from which metal is to be removed, to raise the metal to its.

such a conditioning method and apparatus,

greater emciency and uniformity when starting along a relatively wide zone of the surface to be treated, as well as greater efliciency of the suc- ,ceeding portion of a desurfacing operation; to

provide a surface conditioning method and apparatus which may be timed with greater precision and operated practically automatically from the beginning to the end of a pass to produce uniformly satisfactory results in less time and with less skilled operators thanwere required formerly,

upon are moved relatively to said body and in a direction substantially parallel to the surface to remove a thin layer of metaltherefrom, leaving a bright and clean new surface that is substantially free from defects such as seams, cracks,

and'the like.

When heating flames alone are used to raise a portion of surface metal to the ignition temperatureto start a desurfacing operation, the preheating time may vary considerably. The preheating time for starting at a square cut end edge of a billet generally varies from twelveto thirty seconds for a cold billet and from three to eight seconds for a hot billet. However, it is often desirable to start the operation at a place'other than at the edge of a billet, but it takes a much longer timeto heat such a place to an ignition has been difficult and expensive, and unsatisfactory results have been obtained.

The principal objects of this invention are to provide an improved method and apparatus for thermochemically conditioning the surfaces of ferrous metal bodies, such as blooms, billets, slabs, and the like, which method and apparatus shall minimize and substantially OVPl'i-xdtfi the disadvantages discussed above. Other and more specific objects are: to provide an improved method and apparatus for substantially reducing the starting time and other difficulties involved in an operation for thermochemically removing a relatively wide and thin layer of metal flQm the surface of a ferrous metal body; to provide, in

The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, the apparatus embodying features of construction, combinations and arrangement of parts adapted to effect such steps, all as exemplified in the detailed disclosure hereinafter set forth.

For a fuller understanding of the nature and I objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings, in

which:

Fig. 1 is a fragmentary perspective view of a desurfacing machine embodying features of this invention;

Fig. 2 is a view, partly in section, of the work, and partly in rear elevation, illustrating the position of the starting rods after the desurfacing operation has started;

Fig. 3 is a view of a vertical section taken on line 3-3 of Fig. 1;-

Fig. 4 is an elevational view, in section, of a. modified form of apparatus;

Fig. 5 is an elevational view of a further modifled form of apparatus;

Fig. 6 is an enlarged sectional view taken along the line 66 of Fig. 5 showing the construction and arrangement of the starting rod gripper, and

Fig. 7 is a wiring diagram of the electrical control apparatus whereby automatic operation of a .desurfacing machine is obtained according to the invention.

In order to accomplish the removal of surface metal from ferrous metal bodies, such as from ingots, blooms. billets, and the like, for the purpose of eliminating checks, seams, cracks, and other defects in the surface, steps are taken and an apparatus provided in the practice of the present invention, by which combustible metal is heated at least to its ignition temperature and deposited substantially uniformly along a relatively long and narrow heated zone where the metal removal is to be started. While the combustible metal is adjacent the heated zone and at a temperature which is at least its ignition temperature, a substantially continuous, wide stream of oxidizing gas is caused to impinge substantially simultaneously on both the heated zone and the combustible metal, in order to oxidize the latter so that the exothermic heat liberated by the oxidation quickly and uniformly raises to its ignition temperature at least a part of the heated zone against which the stream of oxidizing gas is directed.

As soon as the surface metal of the initial or starting zone against which the stream of oxidizing gas impinges, is raised to its ignition temperature, relative movement of the stream and the body is caused to take place, whereby a thin sheet or skin of metal is removed from the body or work, to leave a new, bright surface more or less free from checks, seams, cracks, and other defects according to the depth of the cut, or other manner in which the operation is carried out.

To this end there is provided, in accordance with the present invention, an apparatus havinga number of blowpipesspaced closely enough together so that the streams of oxidizing gas merg to produce a wide, but transversely rather narrow, continuous stream of oxidizing gas. A suit,-

ably wide heating flame and wide oxidizing stream of gas can be produced by the wide mouth nozzle disclosed in application Serial No. 107,334, now United States Patent No. 2,267,405.

Associated with the blowpipe nozzles, there is provided a row of starting rods in position to deposit metal along the heated zone, together with mechanism for feeding the rods' into the preheating flames and the oxidizing stream, preferably so that the metal is deposited along the heated Zone only to thus expedite the start of the cutting operation at or during the start of the operation. The rods may be so closely spaced together, relative to one another, that the metal is deposited in a substantially continuous line or path along the heated zone. It has been found, however, that satisfactory starting is obtained over a relatively long, narrow starting zone in accordance with the present invention, when a starting rod is provided for each one of a number of nozzles as shown in Figure 1.

When a cut is started on cold work by causing a stream of cutting oxygen to impinge on a small globule of molten metal deposited on the work surface, the cut starts at the place at which the molten metal is in contact with the work sur-- face. As relative movement of the stream and the work starts and the cut progresses. the molten metal and the slag resulting therefrom, spread over the work surface to broaden the cut.

' Usually about one or two inches of relative movement between the work surface and the nozzle is required for the cut to broaden to the full width normally out by a single nozzle of the-type shown in Figure 1. Where only one. of a number of nozzles simultaneously employed. is provided with a starting rod positioned as in Figure 1, as much as about five to six feet of relative movement may be required for the entire cut to be widened to the full width normally cut by the row of nozzles. Accordingly, where it is desired that the out be widened to the full width normally cut by a row of nozzles, preferably at least one starting rod is provided for each such nozzle. In other arrangements, such as those where nozzles having a wide mouth or slotted oxygen or preheating gas passages are employed, the starting material may be disposed and distributed alone Y pared with feeding a length of a cut uniformly along a zone the zone where the desurfacing operation is to be started in any manner desired for quick and efficient starting in accordance with this invention.

Feeding the starting wires or rods at an angle to the work surface has been found to give greater economy in the amount of wire used, as comwire substantially parallel to the work surface and extending along the heated zone. For instance, it has been found that when the starting rods are fed at an angle to the work surface, a total of about three inches in length of starting rod will suffice to start a out about eight inches wide, as against eight inches of wire required if it is fed substantially parallel to the work surface and along the heated zone in the case of a row of nozzles of the type disclosed in Figure 1.

In removing a skin or thin layer of metal from various types of ferrous metal bodies or objects, in accordance with this invention, it may be desired to avoid removing metal from certain portions of the work while removing it from other portions, contiguous therewith, in accordance with some predetermined pattern. To this and certain of the nozzles of a row, or bank, may be blocked off, or the gas passages to them closed, or combustible metal for starting the cut may be supplied to certain of the nozzles at an appropriate time relative to the starting of the cut with other nozzles, as the case may be.

If a flame, such as a wide oxy-acetyiene flame as may be used for heating the starting zone, is used for heating the ox-idizable metal to its ignitlon temperature or for melting it, a very satisfactory material for starting the cut is a rod of iron, or an alloy high in iron. If, in starting in accordance with starting rods are is preferable that this invention, a number of to be used along the zone, it they be selected of sufficiently uniform size and composition for that purpose. Uniformity of the period of time required to heat the metal to its ignition temperature, or to melt it, and, accordingly, uniformity in starting zone, is favored by uniformity of conditions with respect to size of the rods, intensity of the heating flame along the zone, and the like. For uniformly starting a out along a wide zone with a ferrous metal rod of circular cross section, a. rod about 1: inch in diameter is very suitable, although rods of larger or smaller diameter may be used. Such rods are relatively stiff and, when suitably disposed with reference to the work surface, may advantageously be fed by gravity.

Another shape of wire or'rod, other than circular, which has been found to give satisfactory results is a flat, ribbon-like wire. Such a wire, having the same cross-sectional area, or yielding substantially the same quantity of combustible metal by incremental lengths introduced into the preheating flame, as a given circular rod, may be rolled into compact flat coils occupying a relatively small space. The flat wire is most readily melted by so feeding it into the flame that the flame impinges on the narrower side, or edge, of the wire. Edge feeding of flat wire has the advantage that the time normally required to melt an incremental length, or suitable end portion of the wire may be as little as three seconds or less. If desired, however, the flat wire may be so introduced into the heating flame that the flame impinges on the wide or broad side rather than upon the narrower side or edge. Feeding of the flat wire or rod so that the preheating flame imthe out along the place automatically, as well.

asoaosa pinges on its broad side, favors the widening of the out to the full width normally cut by the nozzle, by tending to spread the flame and the combustible metal. In order to control undue spreading of the combustible metal which may be encountered under certain circumstances, it may be found expedient to use a somewhat greater thickness of rod than might otherwise be required, particularly in the case of flat wire which is introduced broadside into the flame. While the.

oxygen, for discharge by a relatively large central orifice l2. These gases are delivered to the nozzles through suitable and conventional blowpipe meananot shown. Each of the gas supply conduits through which preheating oxygen, preheating acetylene, and cutting oxygen are separately supplied to such blowpipe means is provided with a normally-closed valve for controlling the supply of these gases. These normally-closed valves (not shown) in turn are adapted to be opened by electrical means, such as solenoids PH and C0 of Fig; '7, upon energization.

The plowpipe unit H is provided with a number of rod guiding tubes l3, each of which is adapted to have a starting rod N slidably disposed therein. In Fig. 1, each tube I3 is shown so disposed that its downwardly extended longitudinal axis intersects that of the corresponding nozzle 8 at about the surface S of the work.

preferably impinge on the narrower edge of the flat wire or ribbon.

heat the surface metal of the work to the ignition temperature may be so selected and established as to obtain a substantially uniform preheating time for work which is more or less alike, or along a zon where a cut is to be started. Accordingly, the preheating time can be predetermined with sufficient precision from the time the feeding and heating of the combustible metal is initiated until the surface metal of the work is heated to its ignition temperature, as to permit of automatic timing or measuring of the interval. At the end of the measured time or interval when the surface metal of the work is at its ignition tempera ture, the cutting oxygen valve may be automatically opened so that cutting oxygen is caused to impinge at or along the heated place when the cut is to be started, and relative movement of the nozzle and the work caused to take These automatiits spring ll;

cally-operated mechanisms of the present invention may be placed under a common control which may cause the steps or cycles of the process to take place in a particular sequence upon a single actuation of the common control. On the other hand, each of the mechanisms may be provided with independent controls which, however, may also be adapted to cause the steps or the process to take place in a particular sequence upon simultaneous actuation of such independent controls.

Various typ s of interval timers or time delay devices may be used for measuring the preheating time, among which may be mentioned, by wayof example, a synchronous electric motor, if suitable alternating current is available, a fluid escape device, a time delay relay and the like.

Referring again to the drawings, and more particularly to Figure 1, the desurfacing apparatus shown by way of example comprises a conveyor including a roll 6 driven by a motor 7 for positioning and propelling a ferrous metal body W, such as a steel billet, in a direction which may be substantially parallel to its top surface S. Supported (by suitable means, not shown) in a position above the path of such surface S of the work W, is a desurfacing unit H comprising a battery of deseaming nozzles ii mounted in ports 9 of a shoe l0 adapted to rest lightly on the surface S. Each deseaming nozzle is supplied with a combustible preheating gas, such as a mixture of acetylene and oxygen, for discharge by an annular series of orifices I l, and an oxidizing gas, such as Extending transversely'of the tubes l3 and the starting rods N is a shaft 65 which is supported on the unit H. Mounted on the shaft l5 are fingers l6 corresponding, in number, to the tubes l3. Each of these fingers is so mounted on the shaft as to normally engage the rod N under the influence of a tension spring ll which is anchored at its upper end to a cross bar it, and connected at its lower end to the finger it through a hole I 9. At the same time the fingers are so afllxed to the shaft-as by a key, pin, setscrew, or the like-as to turn with the shaft and be disengaged from the rods when the shaft is turned sufflciently. A certain degree of lost motion between the fingers l6 and the shaft I5 is provided to insure that each of the fingers will be free to engage the rod under the tension of Otherwise, if the fingers are attached so rigidly that there is no lost motion between them and the shaft, it would be necessary to set or adjust each of the fingers separately to compensate for any lack of uniformity as might exist in engagement between the fingers and the rods. Thus, the fingers it normally hold the rods N in elevated position above the work surface S. However, when the shaft i5 is turned through a sumciently large angle, the fingers l5 release the rods N which then drop down under the influence of gravity until they rest on the work surface S.

By such a disposition of parts as has been described, and additionally as clearly shown by the drawing, it will be recognized that equal portions of equally spaced starting rods are advanced to a row of equally spaced heating jets and oxidizing jets adjacent a long and narrow starting zone; that the said portions of said rods are fed to said zone by a row of equally spaced starting rod feeding means in order to attain substantially uniform heating of said portions and also their substantially uniform oxidation in order to effect substantially uniform rapid starting of the conditioning operation at all points along said zone; and that preferably all of said rods are disposed in a plane which intersects the plane of the Work surfacealong said zone, namely, the rods are in a plane transverse to the plane of the work surface.

At oneend of the shaft i5 a crank 20 is attached, and this crank 20 is connected to a lever 2! by a link 22, The lever is pivoted to a vertical arm 23 of a bracket 23 mounted on the unit H, and is adapted to be operated by an armature 2-5 of a solenoid RF. The tension spring 26 normally supports the link 22 and the weight of the otherwise unsupported parts connected shaft 28. Each starting wire K is caused to be positively fed into the preheating flame, when the s01en0id RF is energized, by means of a lever 29 secured to the shaft I by a lock screw 30. At its end adjacent the starting wire K the lever 29 is provided with a clutch mechanism 3| including a self-locking detent 32, the arrangement being such th t when the lever 29 is partly turned the detent 3 engages the starting wire K and advances the htterthrough a desired increment. When the sole oid RF is de-energized, the lever 29 with the cl tch 3i is returned to its initial position by a tension spring 33. It is to'be understood that aistarting ribbon or wire K maybe provided for each nozzle 8, the general arrangement being substantially like that shown by Fig. 1.

Still another modified form of wire or rod feeding mechanism is shown in Figure 5. The base or main member I 0| is so mounted in or on the desurfacing machine that the wire is fed into the preheatingfiames so that the flames impinge on the narrow side or edge of the wire. In this modification, the startin rod or wire J is also preferably in the form of a ribbon although wire of other cross section, such as round wire, may be used. The wire J passes from the coil I02 through a movable wire gripper I03, a stationary wire gripper, or brake I04, and a guiding slot in the bar I00 to the deseaming nozzle. The movable wire gripper I 03 is mounted on a movable member I05, which is, in turn, so mounted on the movable links I06, to form one side of a parallelogram linkage, that when the member I05 is moved, it moves substantially parallel to the direction in which the starting rod is to be fed. The movable member I05 is caused to move in a forward direction by a lever I 01 which engages a projection I08 extending laterally from the movable member I05. The. lever I0! is pivoted at one end on a pivot I09, secured to the back of the housing H. At the other end of the lever is an elongated opening or slot IIO for adjustably and pivotally connecting it to the link III at various distances from the pivot. If desired, a shaft similar to I5 may be used in place of the pivot I09 in which case two levers I01 may be keyed to the shaft, one

lever at each end thereof, in position to engage projections I 08 extending laterally from each side of the movable member I05.

Wire grippers I03 and I04 are of similar construction. Each comprises a body portion II2 (Fig. 6) and a cover I I3 which are held together and fastened to the movable member I05, or the base IOI as the case may be, by bolts H4. As

shown in Fig. 6, which is a section taken on line 6-6, a slot I I5 is cut in the wire grippers for 'the flat wire or rod to pass therethrough. In

the bodyportion of each gripper, there is 'a compression spring II6 tending to wedge a steelball III between the wire rod and a race H8 in the block II2 disposed at an angle to the axis of the wire J. In both the m'bvable gripper I03 and the stationary gripper I 04, the ball, the spring, and the angular race are in similar positions relative to the wire, in order that the wire may advance freely through the stationary gripper with forwall motion of the movable gripper, and remain stationary during the reverse motion of the movable gripper.

In the stationary gripper, the ball and spring are in the position shown in Fig. 6 so that, when the wire J is advanced downwardly toward the preheating flames, the advancing wire moves through the gripper in a direction tending to compress the spring. Thus, the ball III in the stationary gripper does not wedge against the advancing wire, and the wire may be advanced freely therethrough. If the wire tends to move in the reverse direction, however, the spring II6 acts to aid the ball in wedging itself between the angular race and the wire thus to hold the latter stationary relative to the gripper I04 and the base IOI. Any movement of the wire in the reverse direction assists the'wedging action of the ball.

When the movable gripper- I03 is moved in the forward direction (downwardly) the ball I I l in the gripper I 03. assisted by the spring and the stationary wire is in a direction tending to compress the spring. Thus, the ball does not wedge between the wire and the angular race, and the movablegripper I03 slides freely over the wire during the return movement.

Means are provided for feeding an increment of wire in a predetermined amount each time the lever I0'I is actuated. An adjustable stud I I9, with locking nut secured to the base IOI and positioned to contact the bottom end of the member I05, limits the forward, or advancing movement of the-movable member I05 and the gripper I03. A long tiebolt I2I, which has one end fastened to the movable member I05, passes through an upper portion IOIa of the base IOI. The other end of the tiebolt passes-through a compressible spring I22 which tends to keep bolt I 2I and movable member I05 in the normal upward or return position. The return movement of-member I05 toward the normal position is limited by adjustable nuts I23 on the threaded portion of the tiebolt I2I below the upper portion I 0Ia of the base. A corresponding adjustment of the movement of the lever I 01 can be made, if desired, by adjusting the position of its connection with the link III at the slot IIO to a greater or, .less distance from the pivot I09.

The feeding action of the mechanism shown in F g. 5 is as follows: When the actuating mechanism, through the lever I01 and the link III, moves the member I05 forward from its normal position, the movable wire gripper I03 advances the wire J through the stationary wire gripper I04 toward the work. When the lever I0'I per mits the member I05 to return to its normal position through the action of the spring I 22, the wire gripper I03 releases its grip on the wire J, and wire gripper I04 grips the wire and prevents its withdrawal away from the work with member scooped open and additionally opens the cutting oxygen iii. The wire grippers I03 and I M and the guiding slot in bar ill will tend to straighten the wire and. remove kinks and bends therefrom. The movable member or plate I05 and the base iiil may be extended to provide space for additional wire grippers I03 and H14 and guiding bars I09. Thus, as many starting wires or rods may be fed as may berequired for the number of deseaming nozzles provided, or the work at hand, or both.

If a number of fiat coils are to be used in a position, relative to the feeding mechanism, sim-.

of convenient arrangement. Another form ofarrangement is to place the coils in a row, each coil positioned relatively to the feeding mechanism as shown in Fig. 4. For edgewise feeding I of the flat wire into the preheat flame, it will be necessary in the latter arrangement for the flat wire to undergo a quarter twist (90 turn) before entering the grippers of the feeding mechanism of Fig. 5. If it is desired to feed the flat wire broadside into the preheating flame, with the mechanism of Fig. 5, the guiding slot in the bar I00 may be so positioned and arranged as to.

impart a quarter twist (90 turn) to the'wire. Alternatively, the flat wire may be fed broadside into the flame, with a. feeding mechanism sim-' ing mechanism as described, and with electrical ly operated controlling devices wired as shown schematically in Figure 7, may be regarded as involving a number of main or principal steps. Before beginning the desurfaclng step itselfi. e. the actual removal of metal from the work surface-the work W is positioned relatively to the desurfacing unit H so that the nozzles 8 will op=-' pressing a push button.

valve. If the apparatus is in more or less continuous operation, however, it should be unnecessary to purge the conduits before carrying out a desurfacing operation. Similarly, the read-- justment 0f the preheat flames or resetting of the cutting oxygen pressure should not be necessary before each desurfacing step is carried out on similar work, or the like.

It is preferred, for reasons of economy in the consumption of the preheating gases, that the preheating flames be so adjustd that their heating intensity is insufiicient to heat the starting zone to the ignition temperature quickly, but rather of suflicient intensity to continue the operation in the desired manner once it has been started by the addition of the supplementary heat generated by the oxidation of the molten or highly heated starting material deposited on the surface in accordance with the present invention. I

The desurfacing step itself may be started as soon as the desurfaclng unit is in proper posi tion relative to the work surface. In accordance with the present invention, the desurfacing may be carried forward by the simple act of de- This causes the preheat valve to be opened, and the resulting combustible gas lets, discharged by the preheating orifices ii of the nozzles 8, are ignited by any shown, or by the heat of. the work surface itself if a hot billet is to be conditioned. At the same crate over the portion of the work surface 8 to" be desurfaced. This positioning is accomplished by manually operating a master switch, which according to the direction in which it is thrown, causes the work-driving motor I of the apparatus of Figure 1 to move the slab W either forward or backward, as the need may be. If desired, however, the desurfa'cing unit H may be M supported as-bya carriage to be moved relatively to the work W which then remains stationary duringthe desurfacing operation. In either case,

additional means (not shown) may be provided to assist in transversely adjusting the dewfacing unit H and the work W relatively to one another.

If the apparatus has inactive for an aping of the conduits and the adjustment of the preheating flames may be accomplished with the aid of a manually-operated purging switch having a first position which holds open the pre heat valves, and (in addition to an oil-position) a second position which holds the preheat valves properly positioned in front of the nozzles. Si-

multaneousiy, a time delay relay is energized, and at the cadet a predetermined interval of time, during which the starting rods or wires are being raised at least to the ignition temperature,

or even melted, the cutting oxygen valve is opened and the motor controller is actuated, driving the work W forward and resulting in a progressive desurfacing process over successive zones or areas.

When the end of the area to be desurfaced has been reached, depressing either another push button, or throwing the master switch into either p a forward or'reverse position, causes all of the g to be shut oil. and the process to stop. If

the operation has been stopped by means of the preciable period of time, it is preferable before master switch, the work W itself will continue tobe moved in the direction of travel determined by the position of the switch, until stopped by returning it to the on position. Further desurfacing can be accomplished by a repetition of the above procedure. Should it be desired to carry on the desurfacing manually, without the rod feed, this can be accomplished by positioning the work as before, then moving the purging switch into its first position for preheating. When this is accomplished, the desurfacing is carried out by simultaneously throwing the purge ing switch into its second position, and throwing the master switch to its forward position. .At the conclusion of the desurfacing operation the purging switch is released and movement of the work W is governed through the master switch. The electrical circuit, Figure 7, preferably comprises a pair of conductors LI and L2 that are connected to a direct current power supply by line switch 36 through safety fuses 31. When I the purging switch PS is moved to the first or to its second or cutting position, its normallyopen contacts PS-2 are closed, thereby energizing a circuit which includes the solenoid CO controlling the cutting oxygen valve.

Positioning the work W preferably is accomplished by the manual operation of the master switch MS having normally-closed contacts MS-O, and normally-open contacts MS--F and MS-R. The normal position of this switch is in the of! or neutral position. The other two positions, one on each side of the center, are for controlling the direction of travel of the work W. The normally-closed contacts MSO are opened when the switch is in either the reverse or for-. ward position. The contacts MS-F are normallyv open, but are closed when the master switch is thrown into the forward position. The

contacts MS-R also are normally open, but are.

closed when the master switch-is thrown into the reverse position. d When this positioning master switch is thrown into the forward position, the contacts MS-F are will be opened by the'forward contacts MS-F of closed and a circuit is energized whichincludes a normally-closed switch controlled by a stop-Q push button S--PB, a normally-closed reverse relay switch RI, a forward relay winding F, a normally-closed travel-limiting switch 42, and

normally-closed accelerating relay auxiliary contacts IAC. When the forward relay winding F is energized through the above circuit, the motoris'started by means of a circuit including normally-open forward relay contacts FC of the relay P, which are now closed, the motor armature A, normallyclosed reverse relay contacts RC, a portion R2 of a dynamic braking resistor 46, a field fluttering contact relay coil FA. and a starting resistor 51. The accelerating relay winding IA is connected in parallel with the armature A of the motor I. As the motor accelerates, the voltage across its vided for as will be shown in the followingdescription.

With an established circuit including normallyclosed auxiliary accelerating relay switch IA2, and the motor field winding 52, full field excitation is provided during the starting period. After the motor has accelerated to the point where the accelerating relay winding IA is energized, its auxiliary contacts IA2 open. When this occurs there is energized a circuit including the field rheostat 53, normally-closed quick return contacts CRI, CRI and the motor field winding 52. This sudden change of field current will cause the armature current (and hence the torque) to rise to higher values, consequently increasing the motor speed. This increase in armature current causes the field fiuttering relay winding FA to close normally-open contacts FAC which are in parallel circuit relation with the auxiliary accelerating relay switch IA2, the field rheostat 53 thus being short circuited. The subsequent increase of speed and decrease of armature current will cause the motor field fluttering or accelerating relay winding FA again to drop out, and the previous1yclescrlbed process will continue to take place until such time as the armature A of motor I has come up to the preset speed.

When the positioning'master switch is returned to the of! position, which occurs when the ma'chine is to bestopped, the forward relay winding F will be de-energized because its circuit A braking through the local circuit comprising'resistor 46 and the normally-closed reverse relay contacts RC.

A minimum field excitation for the dynamic -braking is necessary and is obtained through the circuit including normally-closed auxiliary reverse relay switch RS, 9. normally-closed auxiliary forward relay switch Fl, 9. tap 51 on the rheostat 53, normally-closed quick return relay armature A will increase. When it reachesthe value for which the accelerating relay has been set, its normally-open switch lAS will close,

thus short circuiting the starting resistor 41, and

connecting the coil FA directing to conductor L2. Its auxiliary contacts IAC, in the circuit 4 of the forward relay winding F-will open, introducing resistor 5| in series in the forward relay circuit. This is done because the coils of the forward and reverse relays are not designed to 'operate continuously at full line voltage. The field circuit 52 of the motor I is energized through three substantially independent circuits,

and is so designed as-to give sufilcient field excitation and thus good acceleration regardless oi contact CRI and the field winding 52 of the motor 1.

When it is desired to reverse the direction of travel of the work W, the positioning master switch is moved to its reverse position; whereupon .there is established a circuit including the more I ,mally-closed stop push button switch 35, the

the setting of a field rheostat 53. Since the mo- 'tor l is shunt wound, the armature starting current and torque are dependent upon the field current; but due to prior setting of the desired desurfacing speed, this field excitation might be extremely low andconsequently poorstarting would result. In addition, for best results when using dynamic braking, some field excitation must be obtained. These features all are proclosed reverse contacts MS-R of themaster switch, a normally-closed auxiliary switch F2 01 the forward relay, the coil R of the reverse relay, final limit switch 42, and switch IAC of the accelerating relay. In parallel circuit relation with the reverse relay coil R is the quick-return relay coil CR, and a protecting resistor 62, of the quick-return relay, which is useful -whcnthe head H is operated relatively to stationary work, but which may be omitted when the work itself is moved oiily in one direction. This quick-retum relay is energized at the same time that relay coilR is energized.

The reverse direction of rotation of the armature A of the motor I is accomplished upon the energization of a circuit including the normallyopen but now closed contacts RCI, through the armature A in the direction from terminal A2 to terminal Al, normally-closed main contacts FCI, resistor portion R3, the relay coil FA and the accelerating resistor 41. The field flutter- I coil X.

ing relay winding IA will cause such relayto act as before, except that for the reverse direction, when no desurfacing is being done, the

highest speed is desired, and is obtained independently of the setting of the rheostat 53 by means of the quick-return relayCR. This high.

speed return is obtained by energizationofthe quick-return -relay CR. Upon energization of the relay CR the contacts CR2 close, short-cir v cuiting the rheostatfl, and contacts CRI open,

thereby introducing a resistance," into the cir. cuit including the motor field winding 52. a

With the desurfacing unit.H positioned-over the work W tobe desurfaced,simply depressing thastarting push button. PB, or 34, will cause the entire operation automatically to proceed,

because there 'is'energized a circuit including the normally-closed switch 35, the normallyclosed contacts MS- O of the master switch which must be left in the oif position, the push button switch 34, or PB, and the preheat relay winding X. Energizing relay winding X causes I the contactsfXC to close and thus energize the circuit incl ding the solenoid'PHwhich thereupon opens the preheating gas valves. Relay X,-

when energized, also causes a bridging circuit ing, circuit includes the contacts XI (of. relay X), contacts PS-A of the purging switch PS,

'- which contacts are normally closed when the purging switchis in the off position, and relay Simultaneously, energized'through a circuit including contacts PS-B of the purging switch, a normally-closedswitch TB! of the time delay relay and relay coil Y.

This causes normally-open contacts YC to close and energize the rod feeding solenoid RF,

thereby causing a measured length of starting wire cr'rod (K, J or N) to be introduced into relay in the circuit including coil Y. When this relay coil Y is de-energlzed, its main contacts YO open the the'rod feed solenoidRF,

As pointed out above, whenstarting a cut, the desurfacing head H is positioned above the surface S of the work W and the starting rods or wires are fed, or dropped'until stopped by the surface of the work. The preheating gases melt the lower ends of the rods or wires and the cut is started automatically in approximately or slightly less than three seconds at any desired point on the surface of the work. Simultaneously with starting the cut, or slightly befor, the solenoid is de-energized and the rods are secured so that they cannot feed down-- wardly, as shown in Figure 2.

While the invention has been disclosed in connection with the art of desurfacing, it will around PB '(34) to be completed. This-bridgthe rod feed relay coil Y is be understood by those skilled in the-art that it is applicable to other processes involving the.

.thermochemical. conditioning of ferrous metal,

. such as gas severing and metal treatments involving the combustion of metal. 1 The disclosed apparatus is automatic in 'opheating oxidizable metal at least to its ignition the preheating flames discharged by the nozzles 8.. When the solenoid armature 25 has completed its downward travel, normally-closed switch RFC is mechanically opened by said.

armature 25, and a resistor 68 is inserted in the circuit of the'solenoid RF. This feature is necessary because the solenoid RF is not designed for continuous operation at 230 volts, the preferred voltage of the power circuit. The third simultaneous operation that takes place whenthe cut is started by gneans of the temperature adjacent to and along saidzone and simultaneously depositing such heated metal at a plurality of closely spaced placesthroughout the length of said zone; simultaneously directing a plurality of separate Jets of oxygen oblique- -ly toward said starting zone and the hot metal deposited therealong, said jets being so spaced and positioned relative to each other as to merge to form a continuous wide stream extending throughout the length of said starting zone, and

' said jets and said places of metal deposit beingstarting push button PB, is the initiation of a I predetermined time relay period by the energization of a circuit including the coil TD of the time delay relay. The energization of this timing relay coil TD is adapted preferably to remove a restraining force on a mercury dashpot mechanism, for example, which controls the contacts TDI, TDZ, and TD3 of the timing device. At the expiration of the metered time interval, the cutting oxygen valve .is opened, the

work is started forward, and the rod feed solenoid RF is de-energized.

The cutting oxygen valve is opened through the closing of the circuit including the main preheat relay contacts KC, time delay relay contacts TD3 and the cutting owgen valve sole=- noid CO. The work W- is propelled forwardly by the motor I which is energized when the circuit including relay-oontacts TDI is ener gized, as described previously in connection with the forward travel of the motor. The circuit for the rod feed solenoid RF is 'de-energi'zed by .the

- opening of the contacts TB! of the time delay so spaced along said starting zone that each of said separate jets is directed against one of said deposits of heated metal, to burn said'hot metal and. thereby produce enough exothermic heat to quickly raise to its ignition temperature the adjacent portion of said surface area; and thereupon causing movement of said body relatively to said wide stream while directing the latter against said surface area to progressively desurface said surface area.

2. A process of initiating the thermoch'emical reaction between a body of ferrous metal and a plurality of jets which merge to form a substantially unitary stream of cutting oxygen movable relatively to said body so as to react thermochemically with an initial and successive zones along the surface of said body, comprising introducing a plurality of combustible ferrous metal starting rods into the region of said initial zone and into the path of said stream or cutting oxygen; preheating a portion of each ofsaid rods to the combustion temperature for re-; action with said stream, the heat generated by' said reaction assisting in preheating said initial zone for reaction with said stream; and so coordinating the steps of said process that said the rod feed relay circuit including stream of cutting oxygen is turned on and such relative movement initiated at an automatically metered time interval subsequent to the time that said preheating operation is commenced, said metered time interval being determined by the period required to preheat said rods to the combustion temperature.

3. A process of thermochemically conditioning a substantially wide surface of a ferrous metal body which comprises directing a wide heating medium against a surface of said body to provide a relatively long but narrow heated starting zone extending across the surface; so introducingthe ends of a plurality of spaced, ferrous metal starting rods in the form of flat wires or ribbons into the heating medium at the start of a conditioning operation that a small portion of each wire is heated to at least the ignition temperature, said wires being inclined to said surface of the body and also being so positioned that such heated portions are located at a plurality of closely spaced places along said zone; impinging a wide stream of oxidizing gas against such heated wire portions and also against the heated surface metal along said zone; and thereupon moving said body and said oxidizing gas stream relatively to each other in such a direction that said stream progressively thermochemically conditions successive portions of said surface of the body.

4. Apparatus for thermo-chemically conditioning ferrous metal bodies comprising 'a blowpipe including a nozzle for directinga heating medium against an area of an upper, substantially horizontal surface of such a-body to provide a heated starting zone and also for directing an oxidizing gas jet against said heated zone; means for effecting relative movement between said body and said blowpipe in a. direction generally parallel to said surface; means for guiding a starting rod of ferrous metal downwardly into the region of said zone where a portion of said rod may be heated by said medium and oxidized by said gas; means normally maintaining said rod in a fixed position relative to said blowpipe and said surface; and means for momentarily releasing said ro d whereby said rod descends along such guiding means and under the influence of gravity until its lower end engages said surface.

5. In an-apparatus for thermo-chemically conditioning ferrous metal work such as a steel billet, means providing a stream of cutting oxygen directed against a zone extending transversely of the length of a surface of the work; means providing a preheating flame directed against said zone; propelling means for effecting v movement of the oxygen stream along said surface relatively to the work; valves for separately controlling the oxygen stream and the preheating flame; feeding means for feeding starting material into the preheating flame; and common control means which, in response to actuation, is operative automatically in sequence to both open the preheat valve and to operate said feeding means, and subsequently to open the cutting oxygen valve and to operate said propelling means.

6. Apparatus according to claim 5, in which the common control means includes a time delay means which causes the opening of the cutting oxygen valve to occur at the end ofa fixed time interval after thefeeding of said starting material. s

7. A process as defined in claim 3 in which the ciated with said blowpipe ity until their lower ends rest closely r the heating medium is heating medium is a heating flame and the flat wires or ribbons are so positioned relatively to the heating flame that the heating flame impinges on the narrow side or edgeof each of said flat wires or ribbons in order the more quickly to initiate the melting of the wires or ribbons.

8. A process as defined in claim 3 in which a heating flame and the flat wires or ribbons are so positioned relatively to the heating flame that the heating flame impinges on the broad side of each of said flat wires or ribbons in order the more quickly to widen the cut to the full width normally cut by theoxidizing gas. I

9. Apparatus for theme-chemically condi tioning ferrous metal bodies, such as steel billets, comprising a blowpipe unit; means for propelling a body in a direction generally parallel to an upper surface thereof and under said blowpipe unit; said blowpipe unit comprising means for directing a heating medium against said surface to provide a starting zone extending transversely of the direction of movement of said body, and means for directing a row of spaced oxidizing gas jets obliquely against saidsurface in the region of said zone; guiding means, assounit, for guiding a row of spaced starting rods of ferrous metal downwardly into the region of said zone, said guiding means being so constructed and arranged that said rods will descend along the guiding means under the influence of gravity; means normally holding said rods in fixed position relatively to said blowpipe unit; and means for substantially simultaneously releasing said rods to permit the rods to descend in unison by gravadjacent said zonewhere small portions of said rods may be uniformly heated by the heating medium and oxidized by the oxidizing gas.

10. Apparatus for working ferrous metal, comprising, in combination: a blowpipe unit'pro- 'vided with preheat means for directing a relatively wide heating medium against a work surface to provide a relatively long, narrow heated starting zone extending transversely of the length of such surface; means, responsive to the initiation of said preheat means, for feeding a measured quantity of ferrous metal in the region of said zone, where it is melted by said heating medium and deposited on the work surface heated by said medium; said blowpipe unit being provided with means for directing a relatively wide stream of oxidizing gas against said work surface in said zone; automatic time delay means acting to start the flow of said oxidizing gas at the end of a fixed time interval after the feeding of said ferrous metal to said zone; and propelling means, responsive to the starting of said flow, for moving said blowpipe unit relatively to said work in a direction substantially parallel to such work surface so that a 'wide layer of metal is removed therefrom by said oxidizing gas means.

11. In an apparatus for conditioning work such as billets, means for delivering a stream of cutting oxygen of a substantial width against one surface of the work, means providing a gaseous preheating flame substantially coextensive with said stream, means for effecting movement of the work and the oxygen stream relatively to each other; separate valves for controlling the oxygen for said stream and the gas for the preheating flame; feeding means for 7 the common control means includes flame; andcontrol means which,.in response is operative automatically sequence to both open the preand operate saidfeeding means, to open the cutting oxygen valve, to operate said movement and restore sa'idcontrol means to its initial condition for a repetition of said predetermined sequence.

12. Apparatus according to claim 11 in which in.a.

aeoaoee feeding starting'material into the preheating I of the blowpipe and the -w so to take place that the region of impingement progresses along the surface of'the body in the general direction of the newer the cutting owgen whereby the finally to stop Y lay means whichcauses the opening of the pro-"' heat gas valve and the operation of the movement effecting means to be successive.

. 13. Automatic" apparatus for thermochemi cally removing a layer of metal from at least one surface of a ferrous metal billet, bloom, slab and the like, which comprises, in combination:

flame-producing gas; means for efi'ecting movement of said body relatively to each for controlling the other; and common means opening of said valves, the

flowing gas tends to move the molten slagand molten metal ahead of said region.

15. An apparatuses defined in claim 14 in which the blowpipe is provided with a row of cutting cutting operation. I

' 16. Apparatus for conditioning metal comprising, in combination, blowpipe means adaptagainst azone extending along said guiding means being so constructed and arranged that the metal rods are also disposed at operation of said starting rod feeding means,

and the operation of said movement efl'ecting means. I

14. Apparatus forcag out a desurfacing operation on ferrous metal bodies comprising, in combination: a blowpipe adapted to have while the metal thus deposited is at its ignition temperature; and common control means, including a time delay mechanism, said common control means being arranged to operate in response to actuation at the start of a desurfacing operation to cause one or more starting rods to 1 zle means also having provision for delivering I surface of the body;

"causesaid propellingmeans 18..Appa'ratus for'- thermochemically condi b1o6m, billet, slab and the comprising, in combination, a thermochemical j GOD. 5 :20. h; zone .on a surface of feeding mechanism for feeding fusible,

stream relatively to each other;

structed and ing medium oxidizing medium; ing movement of the tively to each other;

to operate.

tioning a ferrous metal body such asa steel conditioning device having "no'mle means structed and arranged to deliver heating ii adapted to heat a starting thebody; and oxidizable metal into the region of the not ale for heating by the heating -es; said nozstream of a gaseous oxidizingmedium;

for eilecting movementof the which, in response to actuation.

its combustion temperature,

on the oxidizing medium andalsoto like, said apparatus I andsaidf control m V is operativeau body tomatically to turn on the oxidizing medium and to cause said propelling means to operate after said heating flames have been turned on and said metal has been fed by said feeding means.

19. Apparatus for thermochemically conditioning ferrous metal bodies, such as steel billets, comprising a blowpipe unit; means for causing relative movement between the metal body and said blowpipe unit in a direction generally parallel to a surface of the metal body; said blowpipe unit comprising means for directing a relatively wide heating medium against such surface to heat a relatively long and narrow area to provide a long and narrow starting zone extending transversely of the direction of movement of said unit, and means for directing a row of spaced oxidizing gas jets obliquely against said zone; means, associated with said blowpipe unit, for guiding a row of spaced starting rods of ferrous metal into the region of said zone for heating a small portion of each of the rods at the ends thereof by said medium; rod-feeding means for advancing said rods along such guiding means toward said zone; means for operating said rod-feeding means to advance said rods simultaneously into the region of said zone for uniform heating of said portions.

20. Apparatus for thermochemically desurfacing a relatively wide surface area of a ferrous metal body, such apparatus comprising, in combination, a single blowpipe unit carrying a plurality of nozzles constructed and arranged to said blowpipe unit comprising means for directing a relatively wide heating medium against such surface to heat a relatively long and narrow area thereof to provide a long and narrow starting zone on said surface extending transversely of such direction of relative movement, and means for directing a row of equally spaced oxidizing gas jets obliquely against said zone;

means, associated with said blowpipe unit, for

and motion-transmitting deliver a heating medium adapted to heat a por- 1 tion of said surface area to provide a narrow heated starting zone extending across the width of said surface area; and rod-feeding means comprising a row of guides carried by said blowpipe unit in fixed relation to said nozzles and arranged to be aligned with said starting zone, said guides being constructed and arranged to guide and position the ends of a row of rods of oxidizable metal adjacent said zone, whereby the end portions of said rods are melted by said medium and deposited along said zone; said nozzles also having provision for delivering a wide stream of oxygen against said zone and against such deposited metal for removing a layer of surface metal substantially uniform in depth, such guiding a row of equally spaced starting rods of ferrous metal into the region of said zone for heating a small substantially equally sized portion of each of the rods at the ends thereof by said medium; rod-feeding means for advancing an equal amount of each of said rods along such guiding means toward said zone; and motiontransmitting means for operating said rod-feeding means to advance said rods simultaneously into the region of said zone for substantially uniform heating of said portions and for substantially uniform oxidation of said portions to effect substantially uniform rapid starting of the conditioning operation throughout the length of said zone.

22. Apparatus as defined in claim 21 wherein all of said rods are disposed in substantially the same plane, which plane intersects the plane of the work surface along said long and narrow starting zone.

23. Apparatus for thermochemically removing metal from a surface of a metal body, such apparatus comprising, in combination, flame-machining blowpipe nozzle means having combustible gas outlet means constructed and arranged to provide heating means to heat a relatively wide zone of said surface and also having oxidizing gas outlet means constructed and arranged to discharge oxidizing gas against such heated deposited metal being burned by said stream of oxygen and thereby producing enough exothermic heat to quickly raise to ignition temperature all portions of said zone throughout the width of the latter.

21. Apparatus for thermochemically' conditioning a surface of a metal body such as a steel billet, comprising a blowpipe unit; means for causing relative movement between the metal and said blowpipe unit in a direction generally parallel to said surface of the metal body zone; and feeding means operable to simultaneously feed predetermined small amounts of fusible and oxidizable ferrous metal material to a plurality of regions longitudinally of said zone and in front of both said combustible outlet means and said oxidizing gas outlet means, whereby such oxidizable metal material is oxidized by said oxidizing gas to produce additional heat along said zone supplementing the heat applied along said zone by said heating means, and means for operating said feeding means.

24. Apparatus as defined in claim 23 wherein said feeding means includes a plurality of guiding means which are spaced substantially equal,

distances apart one from another, and wherein said amounts of oxidizable metal material are deposited separately but equally to said regions.

JAMES H. BUCKNAM. EDWARD MEINCKE. THEODORE W. E'SELGROTH. 

